The potential role of alcohol as a cofactor in HIV infection and development of AIDS has been suggested by epidemiologic studies, but experimental evidence for the effect of alcohol is lacking, we isolated the peripheral blood mononuclear (PBM) cells from six normal volunteers before and after 40 oz. of beer (1.2 L) or the equivalent dose of ethanol in other alcoholic beverages. These cells were exposed in vitro to HIV virus. There was a significant decrease of resistance to infection after alcohol ingestion as assessed by the number of synctia formed (p less than 0.001) and levels of P24 antigen released in PBM cultures (p less than 0.001). Noninfected cultures done simultaneously showed that alcohol ingestion also decreased the abiltity of lymphocytes to produce interleukin 2 (IL-2) and soluble immune response suppressor factor (SIRS) (p less than 0.001), synthesized preminiarly be helper and suppressor T cells, respectively. Our data strngly suggest that the concomitant use fo alcohol and exposure to the virus through sexual activity or b infected needles used in drug abuse may enhance infectivity by HIV. The Specific Aims below are not mutually exclusive and will contribute towards further elucidation of underlying cellular and humoral events which result in subsequent decrease in the resistance of host to HIV. 1. To further elucidate the alcohol-induced increase in the degree of susceptibility of human peripheral blood mononuclear cells from normal subjects to HIV infection. Amount of alcohol consumption and duration of its adverse effect on the immune system will be examined. 2. To elucidate the underlying mechanisms of ethanol induced immunomodulation at cellular and humoral levels. 3. To seek out agents (e.g., lymphokines, monokines, various growth factors etc.) which might neutralize or reverse the adverse effects induced by ethanol.